Digital communications over twisted copper wire pairs, or optical fiber pairs, are widely used for Local Area Networks (LANs), for example. The LAN typically connects multiple computer users to a server or other computer. A LAN transceiver, that is, a combination transmitter and receiver, is typically used to transmit data and receive data over the twisted pair or fiber pair.
A typical LAN 15 as in the prior art is shown
A typical LAN 15 as in the prior art is shown in FIG. 1. The LAN 15 includes a pair of servers 16 connected to a plurality of user workstations 21. A hub 17 is connected on one side to the servers 16, and on the other side to the workstations 21. The hub 17 includes signal ,transceivers and associated circuitry for processing the signals between the servers 16 and workstations 21.
A simplified prior art hub 17 with the overall housing removed for clarity is shown in FIG. 2. More particularly, the illustrated hub 17 includes a modular jack connector 22, which, in turn, may provide twelve ports 22a for connection to up to twelve workstations 21. A series of electrical conductors, not shown, are carried within each recess of the modular jack connector 22 and engage mating conductors on the corresponding jack or plug. One common port arrangement provides compatibility with a so-called "RJ-45" jack.
Optical ports, such as including an optical detector and optical emitter, are also commonly used to establish inbound and outbound signal paths.
The modular jack connector 22 is mounted onto a mother circuit board 24. The mother circuit board 24 also illustratively mounts three communications processors 26, such as may be provided by available integrated circuit packages. In addition, the mother board 24 illustratively mounts associated magnetic devices 27 for coupling to twisted wire pairs, for example. The magnetic devices 27 are typically small transformers.
The communications processor IC's 26 may be integrated quad-port repeaters such as the Model LXT915 available from Level One of Sacramento, Calif. Each of the communications processors 26 includes four transceivers for connection to four respective ports 22a. The communications processor IC's establish shared communications among the connected ports.
The mother circuit board 24 would also typically mount a number of other components, not shown, such as for supplying power, providing various status indications, etc. An overall housing, not shown, would also typically be provided to protect the mother board 24 and other components. The hub 17 is typically a relatively bulky and expensive piece of equipment.
Board-mounted shielding would typically be needed to shield the communications processors 26 from the magnetic devices 27. The magnetic devices 27 typically generate electromagnetic interference (EMI), and the communications processors 26 are typically susceptible to EMI. The housing may be made of an electrical conductor, to provide an overall EMI shield.
Another disadvantage of prior art LANs including one or more conventional hubs 17, is that the hubs are separate pieces of equipment from the servers 16. The hubs 17 need to be purchased, installed and maintained. In other words, the hubs 17 add cost and complexity, and may reduce the overall reliability of the LAN 15.